(PL/S) An IBM machine-oriented language derived from PL/I, in the late 1960s, for the IBM 360 and IBM 370. PL/S permitted inline assembly language and control over register usage.
Previous IBM 360 operating systems such as OS/MFT and OS/MVT had been written entirely in assembly language. The first IBM OS that had any significant portion written in PL/S was MVS, followed by OS/VS1, OS/VS2 and OS/SVS.
PL/S was part of IBM's OCO (object code only) effort, started in 1983. PL/S was used internally and never released to the public. It is documented in various IBM internal ZZ-? publications.
Versions: PLS1, PLSII.
["PL/S, Programming Language/Systems", W.R. Brittenham, Proc GUIDE Intl, GUIDE 34, May 14, 1972, pp. 540-556].